package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.data.redis.core.StringRedisTemplate;


import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock{

    private StringRedisTemplate stringRedisTemplate;


    //name代表业务名称，也就是在什么业务加锁
    private String name;
    private static final String KEY_PREFIX="lock:";



    //这里使用uuid，在redis里面添加锁的时候增加线程前缀，这样就算是全局唯一id，不然两个jvm可能是同一个线程号，那就搞错了
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
        this.name = name;
    }



    @Override
    public boolean tryLock(long timeoutSec) {
        // 获取线程标示
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        // 获取锁
        Boolean success = stringRedisTemplate.opsForValue()
                .setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unlock() {
        // 获取线程标示
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        // 获取锁中的标示
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
        // 判断标示是否一致
        if(threadId.equals(id)) {
            // 释放锁
            stringRedisTemplate.delete(KEY_PREFIX + name);
        }
    }
}
